Differential feeding mechanism for sewing machines



G. S. GATCHELIQ.'

DIFFERENTIAL EEEDINE` NIEcIIIINIsNI EoII SEWING MACHINES.

v APPLICATION FILED MAR. IUI I9I8. I 1,407,023, Patented Feb. 2l, 1922.

4 SHEETS-SHEET I.

INVENTOR www l y @Mm ATTORNEY G. S. GATCHELL.

DIFFERENTIAL FEEDING IvIEcH/INIsM EGR SEWING MACHINES.

APPLICATION FILED MAR. IU ISIS.

1,407,023, v Patented Feb. 2], 1922.

4 SHEETS-SHEET 2.

ATTORNEY G. S. GATCHELL.

DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED III/m18. 1918.

1,407,023, Patented Feb. 2l, 1922.

4 SHEETS-SHEET 3.

WITNESSES Z INN. OR Qsvfww. W BY ATTORNEY G. S. GATCHELL.

DIFFERENTIAL FEEDING MECHANISNI FOR SEWING MACHINES.

APPLICATION FILED MAR. 18| 19H1.

1 ,407,023 Patented Feb. 21, 1922.

4 SHEETS-SHEET 4.

Hjm WMTNESES l INVENTOR ATTORNEY UNITED STATES PATENT OFFICE.

GEORGE s. GATOHELL, OE ROSELLEPARK, NEW JERSEY, ASSIGNOR To THE SINGER, MANUFACTURING COMPANY, A CORPORATION OE NEW JERSEY,

DIFFERENTIAL EEEDING MEOHANISM FOR SEWING MACHINES.

l Specification of Letters Patent. v Patentd Feb. 21 1922.

original application filed August 10, 1917, Serial No. 185,446. Divided and .this application led March `18, 1918. ,Serial No. 223,111.

To all whom t may cof/wem.'

Be it known that I, GEORGES. GATOHELL, a citizen of the United States, residing at Roselle Park, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Differen-A Mechanisms for Sewing Matia-l Feeding t chilies, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to sewing machines,- more particularly of the multiple-needle length regardless of the length of stroke of the fulling feed member.

A further object of the invention is to provide a differential feeding mechanism which will keep the work closely and accurately under control as it passes from the forward or fulling feed-dog to the main or stitchlen h defining feed-dog.

urther objects of the invention will appear from the following description land claims.

The present feeding mechanism is of the type represented in the a plication of George E. Molyneux, Serial o. 32,269, filed July 5, 1915, although differing therefrom in certain important particulars. In the present instance the main and auxiliary feeddogs are adjustably connected to their actuating means in such a manner that, in all positions of adjustment, the auxiliary feeddog will always assume the same definite position, relatively to the needles, at the end of its feeding stroke, preferably with its last tooth slightly in advance of the VStitching point, while the main feed-dog will always assumethe same definite position at the beginning of its feeding Stroke, preferably with its irst tooth in the position previously occupied by the last tooth of the auxiliary feed-dog. Additional 'adjustments of the feed-dogs relatively to their feed-bars, are

provided for varying the above defined positions of the feed-dogs relatively to the stitchlng point. The machine is, in the present lInstance, equipped with a presser-foot havlng-a pivoted sole-portion cooperating wlth the feed-dogs and including spaced toes between which the upturned marginal portions of material are adapted to be presented and fed toward the stitching point.

ln the accompanying drawings, Fig. 1 is a slde elevation partly in Section, of a sewing machine embodying the present invention. Fig. 2 is a similar view ofthe reverse side of the machine. Fig. 3 is a horizontal section through the standard of the machine above the plane of the work-arm. Fig. 4 1s a fragmentary rear elevation of the machine, partly in section, and with the rear cover-plate removed -toreveal the mechanism housed within the standard. Figs. 5 and 6 are transverse vertical sections through the work-arm along the lines 5-5 and 6 6,

respectively, Fig. 3. Figs. 7 and 8 are side ing bracket-arm 3 terminating in the hollow.

head 4. Secured to the Standard 2 is the ianged rearward extremity of the tubular work-supporting arm 5 which is formed with two angularly arranged flat sides 6, 7 (Figs. 5 and 6) and a curved-upper side 8, whereb v said work-arm is substantially sectorshaped in cross-section. Secured to the front or free end of the work-arm castin is the throat-plate 9. J ournaled in an crosswise of the standard 2, above the level of the work-arm and cro'sswise of the latter is the main-shaft 10 carrying a pulley wheel 11 and hand-wheel 12 both cast integral with a common hub 13.

The main-shaft is formed with a ball-crank 14 which is embraced by the lower strapped end of a pitman 15 the upper strapped end ofwhich embraces a ball-ended crankpin 16 carried by the crank-arm 17 at the rear end of the needle-actuating rock-shaft 18 which is journaled within the bracketarm 3 and, at its forward end, carries a crank-arm 19 connected to the reciprocating needle-bar 20 by means of the link 21. Secured to the lower end of the needle-bar 2O is the needle-clamp-block 22 which, in the present instance, is socketed to receive four -needles nl, n2, n3. and n* arranged in a vertical plane ltransversely of the workarm 5.

Mounted within the end cap 23, in cooperative relation with the needles, is the thread-carrying looper 24; the upper edge of the blade of which is curved concentrically with the curved upper side of the. workarm, Fig. 9, while the lower edge 25 of said blade is but slightly curved or may even be substantially straight throughout a portion of its length.l The shank of the looper is secured to the looper-support 26 by a screw 27. The looper-support is clamped to the front end of the oscillating and endwise movable looper-shaft 28 which is journaled within and lengthwise o-f the work-arm `5 'asj closely as practicable to the apex of the angle formed by the flat sides 6 and 7 thereof, Figs. 5 and 6, said angle being large enough to accommodate the necessary loopseizing and shedding strokes of the looper. The looper-operating mechanism is preferably the same as that disclosed in my said co ending application.

he feeding mechanism is as follows: secured to the main-shaft is the feed-advancing eccentric 29 which is connected by the pitman 30 to the rocker-arm 31 the split ub 32 of which is clamped to the cross-shaft 33 to which shaft is also clamped the split hubs of the `main feed-advancing rockerarm 34 and the auxiliary feed-advancing rocker-arm 35. The main feed rocker-'arm 34 is formed with a curved slot 36 in which is adjustably secured a pin 37 connected to one endof a link 38 the o posite end of which is pivotally connecte to a lever 39 depending from afixed fulcrum-pin 40 which extends across and within the standard 2 in parallelism with the main-shaft 10. Thevlower end of the lever 39 is pivotally connected to the rearward end of the main feed-bar 41 which extends within and longitudinally of the work-arm and, at its forward end, carries a screw-pin 42, Fig.- 3, which passes through the slotted shank 43 of the main feed-dog 44 and serves to secure the latter to said bar while permitting adjustment of the feed-dog lengthwise of said bar. When the main feed-dog is at the forward end of its stroke, Fig. 8, the slot 36 assumes a position concentric with the point of pivotal connection between the link 3.8A

andthe lever 39 so that the main feed-dog will always assume the same forward pos1' tion regardless of the position of adjustment of the pin 37 in the slot 36. The main feeddog 44 is preferably so adjusted on the main feed-bar that the front tooth of said feeddog will rise into engagement with the fabric in a position'somewhat in advance of the needles, as shownin Fig. 8.

The auxiliar witha curved s ot 45 in which is fitted a pin feed-rocker 35 is formed- 46 carried by the rear end of'a link 47 the front end of which is pivotally connected to a lever 48 depending from the fulcrum-pin 40. -The lower end of the lever 48 is pivotally connected to one end of a link-section 49, the opposite end of which carries a fixed pin y50, and a screw 51, both extending through the slot 52 in the rear end of the link-section 53, the front end of which is pivotally connected at 54 to a bracket 55 screwed to the side of the auxiliary feed-bar 56 which is deeply recessed or grooved at its Preferably the link-sections 49 and l53 are so adjusted that the rear tooth of the auxiliary feed-dog will end its feeding stroke at I the same position, somewhat in advance of the needles, at which the front tooth of the main feed-dog begins its feeding stroke. Thus, a uniform stitch-length will be secured regardless of the degree of falling action of the auxiliary feed-dog. By varyin the adjustment of the link sections 49 an 53 relative to each. other, the point at which the auxiliary feed-dog 457 ends its 'feeding stroke, may be varied. J

The fulling feed may be vl'readily `adjustedwhile the machine is in operation by means of the treadle-controlled lever-arm 58 which is mounted on the rock-shaft '59 fulcrumed ,on the standard 2 and carrying a lever-arm The main and auxiliary feed-bars are supported within the work-arm on a fulcrumblock 65 which is fitted within the slot 66 in the main feed-bar and is carried by the fulcrum-pin 67 supported, in turn, at the -forward kend of the feed-lifting lever 68 presser-foot comprising, in the present instance, a sole-piece 72, F ig. l, pivoted at 7 3 to the shank 74 secured to the lower end of the usual spring-pressed presser-bar 7 5.

Having thus set forth the nature of the invention, what 1 claim herein is 1. A sewing machine comprising, in combination, stitch-forming mechanism including a reciprocating needle, and differential feeding mechanism including auxiliary and main feed-dogs arranged respective y in front and in rear of the needle-path, adjustable actuating connections for said. front feed-dog permitting variation of its feeding stroke While maintaining a fixed ending point for said stroke relatively to the needle-Y path, and adjustable actuating connections for said rear feed-dog permitting variation of its feeding stroke while maintaining a fixed beginning point for said stroke relativelly to the needle-path.

.2. sewing machine comprising, in combination, stitch-forming mechanism including a reciprocating needle, and differential feeding mechanism including auxiliary and main feed-dogs` arranged respectively in front and in rear of the needle-path, adjustable actuating connections for said front feed-dog permitting variations of feeding stroke while maintaining a fixed ending point for said stroke relatively to the needlepath, and adjustable actuating connections for said rear feed-dog permitting variation of its feeding stroke while maintaining a fixed beginning point for said stroke relatively to the needle-path, and means permitting adjustment of said'feed-dogs to vary said ending-and beginning points. v

3.. A sewing machine comprising, a frame including a hollow standard, a hollow workarm carried thereby and projecting forwardly therefrom and a bracket-arm carried by said standard and overhanging said workarm, a main-shaft journaled crosswise of said standard and Vwork-arm, a feed-rocker mounted within said standard to oscillate about an axis parallel tosaid main-shaft and including main and auxiliary feed-actuating rock-arms, main and auxiliary feed-bars extending within and lengthwise of said workarm, and independently adjustable operative connections between said feed-bars and said rock-arms,

4. A sewing machine comprising, in comof its feeding stroke.

bination, stitch-forming mechanism including a reciprocating needle, main and auxiliary feed-dogs arranged, respectively, in rear and in front of the needle-path, main and auxiliary feed-bars carrying said feeddogs, a main-shaft, driving connections between said shaft and said auxiliary feed-bar including a slotted rocker-arm, a link ad- Ajustably connected at one end to said rockerarm, said rocker-arm being curved to assume a pos'tion concentric with the opposite end of sai link when the auxiliary feed-dog is at the ending point of its feeding stroke, and driving connections between said shaft and the main feed-bar including. a slotted rocker-arm, a link adjustably connected at one end to said rocker-arm, said rocker-arm being curved to assume a position concentric with the opposite end of said link when the main feed-dog is at the beginning point 5. A sewing machine comprising, in combination, stitch-forming mechanism including a reciprocating needleand dierential feeding mechanism including auxilia and main feed-dogs arranged respective y in front and in rearof the needle-path, and adjustable actuating connections for said rear feed-dog permittlng variation of its feeding stroke while maintaining a fixed beginning poiplt for said stroke relatively to the needlepat l 6. A sewing machine comprising a frame formed with a hollow standard and a hollow work-supporting arm free at one end and at its opposite end joining said standard, main and auxiliary feed-'bars extending within and lengthwise of said work-supporting arm, a main-shaft journaled within said standard and extending transversely of the work-supporting arm, a pair of swinging levers fulcrumed within said standard and connected, respectively, with said feed-bars, a feed-rocker fulcrumed within said standard and including main and auxiliary feedrocker-arms, and adjustable link connections between said feed-rocker-arms and said swinging levers.. i.

7. sewing machine including .in combination a work-supporting arm, a main feed-dog and an Vauxiliary feed-dog disposed at one end of said work-supporting arm,a feed-bar extending lengthwise of the arm and carrying said main feed-dog, a feed-bar extending lengthwiseofthe arm and carrying said auxiliary feed-dog, means for raising and loWeringthe'feed-bars, means for imparting backward and forward -movements to said bars including a rocking frame at the opposite end of the work-supporting arm from the feed-dogs, means connected to an arm on the rocking frame for oscillating the same, an upwardly projecting arm fixed Ato said rocking frame and having a se mental slot, a link connecting the main feedbar to said arm, said link having an adjustable connection with said slot, a second arm fixed to said rocking frame and having a segmental slot,- a link connecting the auxil- 5 iary 'feed-bar to said second arm, said link having an adjustable connection withv said slot, 'and manually operable devices for EORGE S. GATCHELL. 

